Electric guitars are often fitted with mechanisms for dynamically changing the tension upon one or more of the sound-producing strings, so as to vary the pitch. By using such a mechanism to alternatively increase and relax tension on the strings, a so-called "tremolo" effect can be produced; reducing the tension from the as-tuned condition results in what is known as a "choking" effect; "note bending" and "detuning" effects can be produced as well with mechanisms of this type.
In their most conventional form, tremolo devices employ a lever which is connected to the bridge block and is disposed on the front of the instrument body near its tail or bottom end; thus, it is positioned for oscillation by the player using his picking and strumming hand. To produce the desired effect, the performer must therefore first play a note or chord and then move his hand to operate the tremolo lever; obviously, he cannot do both at the same time.
Variations in the means for operating pitch varying mechanisms of this type have been proposed in the art. For example, in Glaser, II U.S. Pat. No. 4,354,417, a tone changer unit is disclosed wherein individual strings may be attached to one of three lever arms to enable alteration of their pitch. An extension arm is non-rotatably connected to one of the three lever arms, and is designed to be operated by engagement with the performer's body. The unit is located at the top of the instrument body near the neck junction, and cables are employed to transmit movement of the operating lever assembly to the bridge assembly, and thereby to the strings of the instrument.
A note bender attachment is shown in Borisoff U.S. Pat. No. 4,535,670, which is actuated by body movement through contact with an arm that extends rearwardly from the tail end of the instrument. The actuating arm is evidently disposed to lie alongside of the player's hip when the instrument is held in playing position.
Other U.S. patents show pitch changing devices for stringed instruments which are actuated in various ways. Thus, Lohman U.S. Pat. No. 2,136,627 uses an electrical motor to vibrate the bridge of a guitar, and U.S. Pat. No. 3,382,749 to Watson discloses the similar use of a pneumatic diaphragm. A pedal-operated tuning control arrangement, which is connected from the rear of the instrument, is shown in Jurichek U.S. Pat. No. 2,889,732, and strap-control mechanisms are disclosed both in Parson et al U.S. Pat. No. 3,512,443 and in Fender U.S. Pat. No. 3,686,993.
Kusakawa U.S. Pat. No. 3,910,152 provides a sliding bridge for a stringed instrument, the position of which may be adjusted by pedals connected through the rear of the body. Lundquist U.S. Pat. No. 4,343,220 utilizes the chin rest of a violin, or a chest or hand-operated plunger arrangement, to produce vibrato by oscillation of the bridge, and an external frame is described by Carson in U.S. Pat. No. 4,397,212 for producing vibrato and pitch control in a guitar.
Although the prior art therefore discloses different forms of hand-held stringed musical instruments having dynamic pitch changing mechanisms, which are operated by movement of the instrument relative to the player's body, still the arrangements disclosed are not optimal. The performing styles of modern guitarists are often typified by wide-ranging and vigorous movement, and are inhibited to the extent that such action is dictated by the need to maintain the operating member of a pitch-controlling mechanism for the instrument in a certain position. The musical, as well as the visual, quality of the performance may be significantly affected as a result.
Accordingly, it is a broad object of the present invention to provide a novel apparatus for dynamic pitch variation in a hand-held stringed musical instrument, and to provide a novel instrument incorporating such apparatus, which permits the performer to effectively control the character of the sound produced, while at the same time affording him a wide range of movement.
A more specific object of the invention is to provide such an apparatus and musical instrument wherein the operating member for the apparatus has a portion that is adapted to stably seat upon a body part of the performer, and to remain in place thereupon despite considerable movement of the instrument, and which thereby affords a high degree of control of the sound produced, throughout a wide range of instrument positions.
It is also an object of the invention to provide an apparatus and instrument having the foregoing features and advantages in which the pitch-varying apparatus can be used alternatively for both increasing and decreasing string tension, is relatively uncomplicated and inexpensive to manufacture, and is adapted for facile installation on the instrument both as original equipment and also as an add-on feature.